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Re: [feyerabend-project] Long-lived software

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  • Ward Cunningham
    For the last few years I have focused my full attention on preserving what I believe to be the real promise of objects, namely flexibility. Flexibility is the
    Message 1 of 4 , Apr 24, 2001
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      For the last few years I have focused my full attention on preserving what I
      believe to be the real promise of objects, namely flexibility. Flexibility is
      the ability to make unforeseen changes in a timely way. A long series of
      inventions have addressed flexibility, starting with 'stored program' digital
      computers, then the subroutine call, and now the polymorphic message send. But
      flexibility is a property that programs still easily loose. And the loss is due
      to a failure of design.

      The relationship between design and flexibility is of course complex. Here I
      will only mention two principles, each of which I have found to take more away
      from flexibility than they give back to design. First, the notion of a program
      life cycle admits failure from the start. If we are to have a life cycle, let us
      make it long. One hundred years cannot be beyond reason. Second, analysis as an
      activity to be conducted independent of implementation again presumes
      implementation artifacts to be short lived and of little value. These ideas have
      become self-fulfilling prophesies. Although they apply in the current
      circumstance, they have become barriers to change from that circumstance. They
      impede progress in object-oriented programming.

      The cause of flexibility will not be served by merely discrediting life cycle or
      independent analysis. To make progress we must examine the system of practices
      that have lead to these principles, discard those practices justified only by
      habit, construct new practice where human nature alone is insufficient, and then
      describe the whole with metaphor that implies useful longevity for the programs
      we make. I have many modest proposals. All fall within this framework.

      (from http://c2.com/doc/wood94.html)

      --
      Ward Cunningham
      v 503-245-5633 mailto:ward@...
      f 503-246-5587 http://c2.com/
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